Harriet
I am all for shorter lengths for the following reasons:
Reduced movement after installation (there is an increased rate of movement that is proportional to the length of timber)
looks more like an interior timber flooring.
Easy to handle, transportion costs are reduced.
Easier to install, bending 5.4m lengths of Ipe is not easy.
Makes the use of timber more efficient, less waste is a good thing these days…
Karl